class MyBlockingQueue {
    private String[] data = null;
    private int head = 0;
    private int tail = 0;
    private int size = 0;

    public MyBlockingQueue(int capacity) {
        data = new String[capacity];
    }
    public void put(String elem) throws InterruptedException {
        synchronized (this){
            while (size >= data.length){
                this.wait();
            }
            data[tail] = elem;
            tail++;
            if(tail >= data.length){
                tail = 0;
            }
            size++;
            this.notify();
        }
    }
    public String take() throws InterruptedException {
        synchronized (this){
            while (size == 0){
               this.wait();
            }
        }
        String ret = data[head];
        head++;
        if(head >= data.length){
            head = 0;
        }
        size--;
        this.notify();
        return ret;
    }
}
public class Demo3 {

}
